Sciaenid courtship sounds correlate with juvenile appearance and abundance in the May River, South Carolina, USA

Black drum Pogonias cromis, red drum Sciaenops ocellatus, silver perch Bairdiella chrysoura, and spotted seatrout Cynoscion nebulosus belong to the family Sciaenidae and are commonly found in South Carolina (USA) estuaries. Fish within this family produce sounds that are associated with courtship behavior and spawning. By listening to estuarine soundscapes, we can identify spawning aggregations. In this study, our objectives were to investigate long-term patterns of black drum, silver perch, spotted seatrout, and red drum calling and chorusing (i.e. indicative of spawning) over a 6 yr time span; identify any shifts in seasonal sound production from one year to the next; and examine the relationship between chorusing and young-of-the-year (YOY) abundance collected through haul seines. We found that in years with warmer springs, black drum, silver perch, and spotted seatrout began chorusing earlier and had longer chorusing seasons than in the years with cooler temperatures. Inversely, cooler temperatures during late summer led to earlier and longer spawning seasons for red drum. We detected the appearance of YOY in the estuary approximately 1 mo after initiation of the chorusing season. Silver perch were the most abundant in the spring, spotted seatrout during the summer, and red drum during the fall. Additionally, we found positive correlations between chorusing and YOY abundance. In years with longer chorusing seasons, we detected higher abundance of silver perch, spotted seatrout, and red drum YOY than in the years with shorter chorusing periods. These patterns provide supporting evidence that passive acoustics can aid inmonitoring reproductive output of an estuary.

Automated summary

This study investigates the long-term patterns of sound production and spawning behavior of four fish species (black drum, silver perch, spotted seatrout, and red drum) in South Carolina estuaries. The results show that warmer springs lead to earlier and longer chorusing seasons for certain fish species, while cooler temperatures during late summer result in earlier and longer spawning seasons for red drum. The study also reveals a positive correlation between chorusing and young-of-the-year (YOY) abundance. These findings support the use of passive acoustics for monitoring the reproductive output of estuaries.